<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>太极</title>
    <link rel="stylesheet" href="/myTest/css/ji.css">
    <style type="text/css">
        body{
            background: gray;
        }
        #taiji {
            width: 0px;
            height: 300px;
            border-left: 150px solid black;
            border-right: 150px solid white;
            border-radius: 100%;
        }

        #taiji::before {
            content: '';
            display: block;
            width: 50px;
            height: 50px;
            border: 50px solid black;
            border-radius: 100%;
            background-color: white;
            margin-left: -75px;
        }

        #taiji::after {
            content: '';
            display: block;
            width: 50px;
            height: 50px;
            border: 50px solid white;
            border-radius: 100%;
            background-color: black;
            margin-left: -75px;
        }


    </style>
</head>
<body>

    <div id="taiji"></div>
</body>
</html>